This application is a 371 of PCT/EP02/03703 filed Apr. 3, 2002.
This invention relates generally to cosmetic products and, more particularly, to preparations containing polyether urethanes as viscosity- and consistency-increasing factors.
Polyether urethanes are polymers which are obtained by reaction of alcohol ethoxylates with isocyanates or polyisocyanates.
These compounds have been used for decades in the printing industry. Polyether urethanes differ very considerably in their physico-chemical properties according to the starting materials used and the stoichiometric ratio between them. In printing pastes for pigment printing, they improve the lubricity of the emulsions used (DE-AS 1 081 225). In printing pastes, diisocyanates reacted with ethoxylated aliphatic alcohols having an ethylene oxide degree of 60 to 400 produce a viscosity which enables the quantity of organic solvent used to be reduced (DE-OS 2 054 885) and which leads to brilliant prints. If thickeners containing aromatic diisocyanates are used in these printing pastes, the advantageous properties of the printing pastes can be further improved.
The use of these thickeners in aqueous systems is described in DE 36 30 319 A1. However, in order to obtain readily processable, low-viscosity and shear-resistant substances instead of the above-mentioned thickeners, which represent paste-form, firm products, the polyether urethanes used were prepared from a mixture of ethylene oxide and propylene oxide and aliphatic alcohols with diisocyanates in a fixed molar ratio.
The thickeners used in cosmetic and body care preparations have to meet stringent requirements. First and foremost, they have to show high compatibility and also—if possible—biodegradability so that many substances have to be ruled out from the outset for use in cosmetics. In addition, they should be universally useable in aqueous, emulsoidal, alcoholic and oil-containing bases, readily processable and lead to a rheology which enables the product to be easily applied so that the preparations can be removed and distributed under clean and simple conditions. They are expected to be compatible with many other auxiliaries, more particularly with salts and surfactants. The thickener itself and the other auxiliaries should also lend themselves to incorporation. The thickened preparations are also expected to show stable rheology and an unchanging physical and chemical quality even in the event of long-term storage and changes in pH and temperature. Finally, the thickeners should be inexpensive to produce without causing significant environmental pollution.
In view of this complex requirement profile, it is clear why, even today, there is still a demand for new thickeners in the cosmetics field.
Accordingly, the problem addressed by the present invention was to provide cosmetic formulations which, after addition of only small quantities of a thickener, would be easy to apply and would leave the skin with a pleasant feeling. The formulations would be easy to distribute on the skin and in the hair without leaving a feeling of stickiness behind. They would have improved physical and chemical stability and would be highly compatible with the skin and scalp. In addition, the viscosity and consistency factors would be unaffected by additions of ions and other auxiliaries or by changes in pH and temperature.